LP gas piping should be graded toward the storage tank at a minimum slope of how much?

LP gas piping should be graded toward the storage tank at a minimum slope of 1/4 inch per 10 feet to ensure proper drainage of any liquid that may condense within the piping system. This slope helps prevent liquid from accumulating in the lines, which could lead to improper functioning of the gas system or even dangerous situations such as leaks or blockages.

A slope of 1/4 inch per 10 feet is the industry-standard requirement, which aids in the effective maintenance of the gas piping system's integrity. By having this gradient, any moisture that condenses can flow back to the storage tank, reducing the risk of liquid gas entering the gas-burning appliances and causing operational issues.

The other options, while they might suggest varying degrees of slope, do not meet the established guidelines for LP gas piping. Therefore, following the correct slope is fundamental for safety and efficiency in gas piping installations.